Washing container



Jan. 17, 1967 A. L A 3,298,209

WASHING CONTAINER Filed Dec. 21, 1964 2 Sheets-Sheet l 1977 eA/E Y Jan. 17, 1967 o. A. LAAKSO WASHING CONTAINER 2 Sheets-Sheet 2 Filed Dec. 21, 1964 United States Patent ()fifice 3,298,209 Patented Jan. 17, 1967 3,298,209 WASG CONTAINER Oliver Arrnas Laalrso, Glens Falls, N.Y., assignor to Aktieholaget lfamyr, Karlstad, Sweden Filed Dec. 21, I964, Ser. No. 419,689 Claims priority, application Sweden, Dec. 23, 1963, 14,427/ 63 8 Claims. (Cl. 68-181) This invention relates to an improved apparatus and process for washing cellulosic pulp.

More particularly, this invention relates to an upright cylindrical container for washing of cellulosic pulp which is brought to pass from one end of the container axially through a middle part thereof and from there on to the opposite end of the container, wherein the middle part of the container is divided up into sector-shaped compartments by means of radial partitions, and wherein the container is provided with means for supplying washing liquid and with means for extracting treating liquid from the pulp.

The object of the invention is to make it possible to maintain a continuous supply of pulp to one end of the container and a continuous discharge of pulp from the other end of the container while the greater portion of the middle zone of the container is used for washing of pulp that is held stationary and is not influenced by the continuous flow.

According to the invention, the foregoing object, as well as other objects and advantages of this invention, is attained by the feature that the compartments of the middle portion of the container are closable at the upper as well as the lower end by means of plates having sectorshaped openings therein, which plates are turnable by means of a common central shaft, the sector-shaped openings being mutually coextensive and arranged so as to admit during the rotation of the plates, a flow of pulp through one compartment or a small number of compartments while the plates close a successively changing series of the compartments, the closed compartments at any given time comprising the majority of the compartments in the container.

The invention will be described in more detail herein below and with particular reference to the accompanying drawings in which:

FIGURE 1 is a vertical side elevation, in crosssection, showing details of the washing apparatus according to the invention;

FIGURE 2 is a horizontal sectional view taken along lines 11-11 in FIGURE 1 to show details of a sieve according to the invention;

FIGURE 3 is a horizontal sectional view taken along lines III-III in FIGURE 1 showing details of the lower sieve plate according to the invention;

FIGURE 4 is a horizontal sectional view taken along lines IV-IV in FIGURE 1 to show the arrangement of the compartments according to the invention;

FIGURE 5 is a horizontal sectional view taken along lines VV in FIGURE 1 to show details of the upper sieve plate according to the invention;

FIGURE 6 is a vertical sectional view taken along lines VI-VI in FIGURE 2 to show further details thereof;

FIGURE 7 is a vertical sectional view taken along lines VII-VII in FIGURE 3 to show further details thereof; and

FIGURE 8 is a vertical sectional view taken along lines VIIIVIII in FIGURE 5 to show further details thereof.

In FIGURE 1, the reference numeral 11 designates the cylindrical shell of the container, which has a lower conical portion 13. A suspension of cellulosic pulp having a consistency of e.g. 3 percent is supplied to the conical portion through a conduit 15 connected thereto. At its upper open end the container is widened and forms a circumferential shelf or step 16 to which a tube 19 for the discharge of washed pulp is connected. Along the vertical center line of the container there extends a shaft 21 which is turned by means of a motor in with gear 552 and the upper end of which is supported by a bearing 22, whereas its lower end projects through the bottom of the container and is sealed thereto by a stufling box 23.

Approximately at the level of the joint between the conical portion and the cylindrical portion of the container there is attached to the shaft 21 a double-walled sieve body 31, the inner cavity 33 of which communicates through a passage 35 in the shaft 21 and through a stuffing box 37 outside of the container, with an outlet conduit 39 for liquid extracted by the sieve body.

As shown in FIGURES 2 and 6,. the sieve body 31 consists of three double-walled disc sectors 57, 59, 61 each having a center angle of 60 and separated by sectorshaped apertures, each extending over a center angle of 60. The upper as well as the lower wall of the disc sectors are pervious and preferably provided with perforation apertures, through which the liquid of the pulp but not the fibers can pass.

Above as well as below the sieve body 31, radial arms 53, 60 are inserted between the shell of the container and sleeves 62, 64 for sustaining the shaft 21.

By means of radially and vertically extending partitions 4d, the container is divided up over the greater part of its length into 12 equal compartments. These partitions are inserted between and attached to the cylindrical shell of the container and a central tube 42 which surrounds the shaft 21. The upper and lower edges of the partitions are horizontal and are situated in the same plane.

Attached to the shaft 21 between the sieve body 31 and the lower edges of the partitions 40 is a sieve body 44 composed of an upper perforated fiat horizontal plate 46 and an impervious fiat horizontal plate 47. These two plates are shaped as circle-sectors comprising an angle of approximately 330 and are bordered, in addition to the circular periphery close to the shell 11, by two radial edges which between themselves form a sector-shaped aperture 55] having a center angle of 30. The interior space 51 between the plates 4-6, 47 is closed by a cylindrical wall 53 and radial fiat walls 55, 56. Said space 51 of the sieve body 44 communicates with an outlet conduit 54 through a passage 52 in the shaft 21 and the stufling box 37. V

A further sieve body 66 is attached to the shaft 21 above the partitions 40. This sieve body is of the same design as the sieve body 44 but differs therefrom in that the lower sector-shaped sieve plate 84 is pervious whereas the upper plate 86 is impervious. The cavity 68 of the sieve body 66 communicates through a passage 70 in the shaft 21 and a stuffing box 72 with a conduit 74 for the supply of wash water, e.g., warm or cold pure water or white water returned from a subsequent Wash filter. The open sector 67 of the sieve body 66 is always located straight above the open sector 50 of the sieve body 44 on account of the sieve bodies being rigidly attached to the shaft 21. The perforated faces of the sieve bodies are located closely to the upper and lower edges of the partitions 40 and therefore the sieve bodies always shut off 10 or 11 out of the 12 compartments from communication with the two ends of the container located on opposite sides of the partitioned center part of the container.

At the upper end of the container there is attached to the shaft 21 a discharging device 76 consisting of radial arms 88 having oblique scraping blades 91 which act upon the upper layer of the pulp column raising at the top of the container and which blades 90 gradually move the pulp outwardly towards the peripheral channel 16 from where the pulp departs through the outlet conduit 19.

During the operation, the shaft 21 is turned either continuously or stepwise with an angle of 30 each time. One or two of the compartments communicate with the ends of the container through the open sectors 50, 67, whereas the remaining compartments do not have any other connection than to the exterior conduits 5d and 74 via the passages 52 and 70 in the shaft 21. During the turning motion of the shaft the compartments will be successively opened and connected to the upper and lower ends of the container, as the leading edges of the open sectors 50, 67 progress, whereas at the trailing edge thereof the compartments are successively closed.

The pulp which is supplied through the conduit 15 and which may be mixed with treating chemicals of some kind, e.g. spent digesting liquor or bleaching liquid and reaction products, is relieved of a part of its liquid content when moving past the sieve body 31. The pulp then rises into the compartment that is temporarily opened and displaces such pulp as has been washed earlier. At the upper end of the compartment the washed pulp flows out sideways and fills the whole cross-sectional area of the upper end of the container, from where the discharging device 76 then forwards the pulp into the outlet 19.

In the meantime, the pulp is stationary in all other compartments and is washed by wash water supplied through the conduit 74 and spread through the perforation holes of the sieve body 66 in an even distribution over all closed compartments. At the lower end of the compartments a corresponding quantity of displaced liquid is sieved off by the sieve body 44 and is discharged through the shaft Zll and the conduit 54. The flow can be controlled by control valves inserted in the conduits 39, 54 and 74. The liquid discharged through the conduit 54 contains the last remainders of the original content of chemicals in the pulp or at least the overwhelmingly greater part thereof and may also contain a portion of the wash water supplied. The remaining portion of the wash Water accompanies the pulp out through the outlet 19.

Surface parts of the sieve bodies 44 and 66 located adjacent their open sectors may be impervious, so that wash liquid is not supplied to or extracted from compartments that are not yet completely closed or are about to be opened. In such a case it is possible to perform the washing operation in the closed compartments under overpressure, whereby the effect thereof is raised, simultaneously as the container is open at its upper end and therefore no significant overpressure prevails in those compartments where the pulp is in motion.

Of course, the total number of compartments may be either greater or less than that shown, and the number of simultaneously open compartments may be increased. However, the best effect is obtained when a comparatively small sector is used for a rather rapid feed of pulp and the greatest possible sector area is used for washing of stationary pulp.

It will thus be recognized that the invention may be subject to various changes and modifications by those skilled in the art without departing from the spirit of the invention, except as defined by the appended claims.

What is claimed is:

1. An apparatus for washing cellulosic pulp wherein cellulosic pulp is continuously supplied to one end of the apparatus, cellulosic pulp in a major portion of the apparatus is stationary while being washed, and washed cellulosic pulp is continuously discharged from the other end of said apparatus comprising: an upright cylindrical container; means for supplying the pulp to one end of said container; means for discharging the pulp from the other end of the container; means for supplying washing liquid to said container; means for extracting treating liquid from the pulp; the middle portion of said container being provided with a plurality of fixed compartments and 4% means for successively opening and closing said compartments, whereby pulp may be caused to flow continuously through an open compartment while pulp in a closed compartment is subjected to washing and extraction of treat ing liquid.

2;. Apparatus for washing cellulosic pulp comprising; an upright cylindrical container having a longitudinal axis; means for feeding pulp to the bottom of said container; means for supplying washing liquid to said container; means for extracting treating liquid out of the pulp; and means for discharging washed pulp from the top of the container; said pulp thereby passing from the bottom end of the container axially through a middle portion thereof and then to the upper end of the container; the middle portion of said container being divided into a plurality of fixed vertically disposed, sector-shaped compartments by means of fixed radial partitions; and plates disposed at the upper and lower ends of said compartments, said plates each having sector-shaped openings therein, and said plates being rotatable about the axis of said container, the rotation of said plates thereby closing both the upper and lower ends of said compartments, said sector-shaped openings being coextensive with said sectorshaped compartments and said plates being arranged to admit a flow of pulp through at least one of said compartments during rotation of said plates, the rotation of said plates successively providing a flow of pulp and then closing each compartment.

3. The apparatus of claim 2 wherein said means for supplying wash liquid to said container and said means for extracting treating liquid from said container each comprises a conduit disposed in a shaft passing along the axis of said container, said shaft rotatably supporting said upper and lower plates and transmitting driving motion thereto.

4. The apparatus of claim 2 wherein both the upper and lower plates are each composed of top and bottom walls providing an interior space therebetween, the washing liquid supply conduit and the treating liquid extracting conduit in said shaft each being in communication with said interior spaces by means of an opening passage extending through the wall of the shaft, the walls facing the compartments being pervious such that washing liquid may be supplied and treating liquid may be extracted by communication through said interior spaces and said perforated walls.

5. The apparatus of claim 2 wherein the lower portion of said container is of conical shape, tapering from a narrow bottom portion to an enlarged upper portion, and wherein the upper end of the container is open and provided with a widened area forming a circumferential shelf, said shelf having means for discharging the pulp from the container.

6. The apparatus of claim 2 including a sieve means for extracting treating liquid from the pulp, said sieve means being disposed below said bottom plate, the sieve body consisting of three double-walled disc sectors, each having a center angle of 60 and separated by sectorshaped apertures, each extending over a center angle of 60, the upper as well as the lower wall of said disc sectors being pervious and provided with perforation apertures, the upper and lower walls defining an inner cavity which communicates with a conduit outside the container through which treating liquid can be withdrawn from the pulp and cellul-osic fibers.

7. The apparatus of claim 4 wherein the top and bottom walls of each of said plates have the shape of a circlesector comprising an angle of approximately 330 and said walls are bordered, in addition to the circular periphery of the container, by two radial edges which between them form a sector-shaped aperture having a center angle of 30, the interior space between the walls of each plate being closed by a cylindrical wall and radial flat walls, the interior space in the lower plate communicating with an outlet conduit and the interior space in the 5 6 upper plate communicating with a conduit for the supply References Cited by the Examiner of washing liquid, the open sectors of each plate always UNITED STATES PATENTS being in registration with one another.

8. The apparatus of claim 2 including a discharging 2,764,011 9/1956 Richter 68181 device consisting of radial arms having oblique scraping 5 3,078,703 2/1963 Richter et al. 68l81 blades which act upon the upper layer of the pulp column 3,088,306 5/1963 Richter 68-181 rising at the top of the container and which blades gradually move the pulp outwardly towards a peripheral chan- IRVXNG BUNEVICH Primary Examiner nel at the top of the container from Where the pulp departs through an outlet conduit. 10 

1. AN APPARATUS FOR WASHING CELLULOSIC PULP WHEREIN CELLULOSIC PULP IS CONTINUOUSLY SUPPLIED TO ONE END OF THE APPARATUS, CELLULOSIC PULP IN A MAJOR PORTION OF THE APPARATUS IS STATIONARY WHILE BEING WASHED, AND WASHED CELLULOSIC PULP IS CONTINUOUSLY DISCHARGED FROM THE OTHER END OF SAID APPARATUS COMPRISING: AN UPRIGHT CYLINDRICAL CONTAINER; MEANS FOR SUPPLYING THE PULP TO ONE END OF SAID CONTAINER; MEANS FOR DISCHARGING THE PULP FROM THE OTHER END OF THE CONTAINER; MEANS FOR SUPPLYING WASHING LIQUID TO SAID CONTAINER; MEANS FOR EXTRACTING TREATING LIQUID FROM THE PULP; THE MIDDLE PORTION OF SAID CONTAINER 